Columbia and Harvard led him to become interested in the question of how one could make a one-dimensional wire, and to the epiphany that if a technology were to emerge from nascent work on nanoscale materials "it would require interconnections – exceedingly small, wire-like structures to move information around, move electrons around, and connect devices together". Lieber was an early proponent of using the fundamental physical advantages of the very small to meld the worlds of optics and electronics and create interfaces between nanoscale materials and biological structures, and "to develop entirely new technologies, technologies we cannot even predict today." Lieber joined the Columbia University Department of Chemistry in 1987, where he was Assistant Professor (1987–1990) and Associate Professor (1990–1991) before moving to Harvard as Full Professor in 1992. He holds a joint appointment at Harvard University in the Department of Chemistry and Chemical Biology and the Harvard Paulson School of Engineering and Applied Sciences, as the Joshua and Beth Friedman University Professor. He became Chair of Harvard's Department of Chemistry and Chemical Biology in 2015. Lieber was placed on "indefinite" paid administrative leave in January 2020 shortly after his arrest for making false statement to federal agents. Lieber's contributions to the rational growth, characterization, and applications of a range of functional nanoscale materials and heterostructures have provided concepts central to the bottom-up paradigm of nanoscience. These include rational synthesis of functional nanowire building blocks, characterization of these materials, and demonstration of their application in areas ranging from electronics, computing, photonics, and energy science to biology and medicine. Contributions Lieber's contributions to the rational growth, characterization, and applications of a range of functional nanoscale materials and heterostructures have provided concepts central to the bottom-up paradigm of nanoscience. These include rational synthesis of functional nanowire building blocks, characterization of these materials, and demonstration of their application in areas ranging from electronics, computing, photonics, and energy science to biology and medicine. Nanomaterials synthesis. In his early work Lieber articulated the motivation for pursuing designed growth of nanometer-diameter wires in which composition, size, structure and morphology could be controlled over a wide range, and outlined a general method for the first controlled synthesis of free-standing single-crystal semiconductor nanowires, providing the groundwork for predictable growth of nanowires of virtually any elements and compounds in the periodic table. He proposed and demonstrated a general concept for the growth of nanoscale axial heterostructures and the growth